What is the total number of moles of $C$ atoms and $H$ atoms respectively present in $n$ moles of the following molecule?

Which of the following contains the maximum number of atoms?

Calculate the mass of oxygen present in $0.1 \ mol$ of $Na_2CO_3 \cdot 10H_2O$. (in $g$)

If $10^{20}$ grains are distributed in one second,then the time taken to distribute an Avogadro number of grains is ........ hours.

Natural abundances of $^{12}C$ and $^{13}C$ isotopes of carbon are $99\,\%$ and $1\,\%$,respectively. Assuming they only contribute to the molecular weight of $C_2F_4$,the percentage of $C_2F_4$ having a molecular mass of $101$ is $.....$

Calculate the number of atoms in the following: $(i)$ $52 \ mol$ of $Ar$ $(ii)$ $52 \ u$ of $He$ $(iii)$ $52 \ g$ of $He$